Sound energy

In physics, sound energy is a form of energy that can be heard by humans. Sound is a mechanical wave and as such consists physically in oscillatory elastic compression and in oscillatory displacement of a fluid. Therefore, the medium acts as storage for both potential and kinetic energy.[1]

Sound measurements
Characteristic	Symbols
Sound pressure	p, SPL,LPA
Particle velocity	v, SVL
Particle displacement	δ
Sound intensity	I, SIL
Sound power	P, SWL, LWA
Sound energy	W
Sound energy density	w
Sound exposure	E, SEL
Acoustic impedance	Z
Audio frequency	AF
Transmission loss	TL

Consequently, the sound energy in a volume of interest is defined as the sum of the potential and kinetic energy densities integrated over that volume:

${\displaystyle W=W_{\mathrm {potential} }+W_{\mathrm {kinetic} }=\int _{V}{\frac {p^{2}}{2\rho _{0}c^{2}}}\,\mathrm {d} V+\int _{V}{\frac {\rho v^{2}}{2}}\,\mathrm {d} V,}$

Here:

• V is the volume of interest;
• p is the sound pressure;
• v is the particle velocity;
• ρ₀ is the density of the medium without sound present;
• ρ is the local density of the medium;
• c is the speed of sound.

See also

• Sound energy density

References

1. Müller, G., Möser, M. (2012). Handbook of Engineering Acoustics. Springer. p. 7. ISBN 9783540694601.